The present invention disclosed herein relates to a semiconductor device and a method of fabricating the same, and more particularly, to a semiconductor device having a cooling structure and a method of fabricating the same.
As the capacity of home appliances and industrial systems increases and an electric vehicle (EV) and a hybrid/plug-in hybrid electric vehicle (HEV/PHEV) emerge, the usage of electrical energy sharply increases and a need for efficiently managing a electrical grid using a smart grid increases. Thus, high power semiconductor devices as core components that affect the efficient energy usage, stability, and reliability of electronic equipments become important recently. Also, as RF components and related systems in wireless communication and military service need broad band frequency and high output power, the power density of RF semiconductor devices also sharply increases.
These semiconductors are electronic devices used for converting or controlling electrical power or outputting a high-frequency RF signal and have a characteristic that they operate at a high voltage, a high current, a high frequency, and high output power. For example, the semiconductor devices may be transistors such as a metal oxide semiconductor field effect transistor (MOSFET), a metal semiconductor field effect transistor (MESFET), a high electron mobility transistor (HEMT), a junction field effect transistor (JFET), an insulated gate bipolar transistor (IGBT), and a bipolar junction transistor (BJT), a schottky or PiN diode, and a thyristor. When the semiconductor devices are applied to modules, components and systems, the thermal management of the devices is a core issue that affects the entire reliability. That is, when the thermal management is not properly performed, the semiconductor device is locally heated in operation and a device characteristic thus decreases or internal interconnections are degraded due to the electromigration of atoms forming interconnections. As a result, there is a limitation in that the semiconductor device wrongly operates or is damaged. It is being reported that the fact also appears in a CPU, an ASIC, a micro sensor, a micro actuator, a micro electromechanical system (MEMS), a high electrical power or high output power transistor and diode, accompanying occurrence of a high temperature during operation. The cooling of a device comes to the fore also in a high output power laser diode (LD) and light-emitting diode (LED).
Typical cooling methods of electronic devices include attaching a thick metal base plate and combining a heat sink emitting heat and then performing natural cooling or circulating a coolant with a fan or a pump.
Recently, the device cooling is also performed by further fabricating heat spreaders or a plurality of thermal vias on one or both sides of the semiconductor device. Also, there is an attempt to lower a device temperature by decreasing a thermal resistance using silicon carbide (SiC) or diamond, which is especially excellent in thermal conductivity, as a substrate.
Typical cooling methods have a complex form in which an external cooling device is assembled to the semiconductor device, and has a high thermal resistance because a volume and a thickness are especially large. Also, there is a limitation in that peripheral parts used for cooling are more expensive compared to the semiconductor device. In addition, there is a limitation in that there are needs for a complex semiconductor fabricating process or an expensive semiconductor substrate.